From: Will Deacon <will@kernel.org>
To: Yong Wu <yong.wu@mediatek.com>
Cc: youlin.pei@mediatek.com, anan.sun@mediatek.com,
Nicolas Boichat <drinkcat@chromium.org>,
cui.zhang@mediatek.com, srv_heupstream@mediatek.com,
chao.hao@mediatek.com, Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org, Evan Green <evgreen@chromium.org>,
Tomasz Figa <tfiga@google.com>,
iommu@lists.linux-foundation.org,
linux-mediatek@lists.infradead.org,
Matthias Brugger <matthias.bgg@gmail.com>,
Robin Murphy <robin.murphy@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 3/4] iommu/mediatek: Use writel for TLB range invalidation
Date: Fri, 11 Oct 2019 17:29:51 +0100 [thread overview]
Message-ID: <20191011162950.yg4o77mlaicacne5@willie-the-truck> (raw)
In-Reply-To: <1570627143-29441-3-git-send-email-yong.wu@mediatek.com>
On Wed, Oct 09, 2019 at 09:19:02PM +0800, Yong Wu wrote:
> Use writel for the register F_MMU_INV_RANGE which is for triggering the
> HW work. We expect all the setting(iova_start/iova_end...) have already
> been finished before F_MMU_INV_RANGE.
>
> Signed-off-by: Anan.Sun <anan.sun@mediatek.com>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
> This is a improvement rather than fixing a issue.
> ---
> drivers/iommu/mtk_iommu.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 24a13a6..607f92c 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -187,8 +187,7 @@ static void mtk_iommu_tlb_add_flush(unsigned long iova, size_t size,
> writel_relaxed(iova, data->base + REG_MMU_INVLD_START_A);
> writel_relaxed(iova + size - 1,
> data->base + REG_MMU_INVLD_END_A);
> - writel_relaxed(F_MMU_INV_RANGE,
> - data->base + REG_MMU_INVALIDATE);
> + writel(F_MMU_INV_RANGE, data->base + REG_MMU_INVALIDATE);
I don't understand this change.
Why is it an "improvement" and which accesses are you ordering with the
writel?
Will
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next prev parent reply other threads:[~2019-10-11 16:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-09 13:19 [PATCH v2 1/4] iommu/mediatek: Correct the flush_iotlb_all callback Yong Wu
2019-10-09 13:19 ` [PATCH v2 2/4] iommu/mediatek: Move the tlb_sync into tlb_flush Yong Wu
2019-10-09 13:19 ` [PATCH v2 3/4] iommu/mediatek: Use writel for TLB range invalidation Yong Wu
2019-10-11 16:29 ` Will Deacon [this message]
2019-10-12 6:23 ` Yong Wu
2019-10-14 21:11 ` Will Deacon
2019-10-15 1:51 ` Yong Wu
2019-10-09 13:19 ` [PATCH v2 4/4] iommu/mediatek: Reduce the tlb flush timeout value Yong Wu
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